According to AllThingsD, Microsoft and Twitter are renegotiating their deal that lets Bing suck data from Twitter's real-time feed "firehose." That deal actually preceded the Google-Twitter deal by a couple of months, and gave Bing a leg up on real-time search.

The deal expires later this year.

Next time, Twitter wants to double its license fee to $30 million a year.

Microsoft apparently isn't worried about that -- $30 million is still chump change to a business unit that loses $3 billion a year.

But Microsoft isn't so sure about Twitter's other demands, which include more control over how Twitter results are displayed on Bing, a bigger cut of the money from ads that appear next to tweets, and more links back to the Twitter Web site.

When Google dropped Twitter, it knew it would have real-time data from Google+ to fall back on. And Google and Twitter may end up striking a deal anyway.

Microsoft doesn't have its own equivalent. But it does have an exclusive deal and solid partnership with Facebook, and it may find that Twitter isn't adding that much value.